a level maths mechanics help
A pole vaulter uses a uniform pole of length 4 m and mass 5 kg. He holds the pole
horizontally by placing one hand at the end of the pole and the other
75 cm from that end. Find the vertical forces exerted by his hands.
i'm confused on this mechanics question: i worked through the method and thought i got it right lol but when checking the answers they drew a different diagram: in this question i would assume that the two forces of his hands are both pushing up on the pole to keep it in place, but the answers have done it so that one hand is pushing up and one pushing down? can anyone explain why?
horizontally by placing one hand at the end of the pole and the other
75 cm from that end. Find the vertical forces exerted by his hands.
i'm confused on this mechanics question: i worked through the method and thought i got it right lol but when checking the answers they drew a different diagram: in this question i would assume that the two forces of his hands are both pushing up on the pole to keep it in place, but the answers have done it so that one hand is pushing up and one pushing down? can anyone explain why?
Original post by pkchan
A pole vaulter uses a uniform pole of length 4 m and mass 5 kg. He holds the pole
horizontally by placing one hand at the end of the pole and the other
75 cm from that end. Find the vertical forces exerted by his hands.
i'm confused on this mechanics question: i worked through the method and thought i got it right lol but when checking the answers they drew a different diagram: in this question i would assume that the two forces of his hands are both pushing up on the pole to keep it in place, but the answers have done it so that one hand is pushing up and one pushing down? can anyone explain why?
horizontally by placing one hand at the end of the pole and the other
75 cm from that end. Find the vertical forces exerted by his hands.
i'm confused on this mechanics question: i worked through the method and thought i got it right lol but when checking the answers they drew a different diagram: in this question i would assume that the two forces of his hands are both pushing up on the pole to keep it in place, but the answers have done it so that one hand is pushing up and one pushing down? can anyone explain why?
after looking at the answers more, i realised that my answers are both right in terms of numbers but one was negative (clearly because one force i did as up and it was supposed to be down) - would i still get this wrong if i just recognised in my method that i drew the force the wrong way round and just made it positive - surely there's nothing in the question that indicates which way the forces are going ...
Original post by pkchan
A pole vaulter uses a uniform pole of length 4 m and mass 5 kg. He holds the pole
horizontally by placing one hand at the end of the pole and the other
75 cm from that end. Find the vertical forces exerted by his hands.
i'm confused on this mechanics question: i worked through the method and thought i got it right lol but when checking the answers they drew a different diagram: in this question i would assume that the two forces of his hands are both pushing up on the pole to keep it in place, but the answers have done it so that one hand is pushing up and one pushing down? can anyone explain why?
horizontally by placing one hand at the end of the pole and the other
75 cm from that end. Find the vertical forces exerted by his hands.
i'm confused on this mechanics question: i worked through the method and thought i got it right lol but when checking the answers they drew a different diagram: in this question i would assume that the two forces of his hands are both pushing up on the pole to keep it in place, but the answers have done it so that one hand is pushing up and one pushing down? can anyone explain why?
it helps to see what youve done / mark scheme youre referring to, but just try holding a pole. The COM will both "rotate the pole downwards" (about a pivot which is ~your hand(s)) and provide a vertical downwards force. You need an upwards force to balance the latter (hand 75 cm from end) but also a downwards force (hand at the end) to counteract the rotational moment as the pole will pivot about the 75 cm hand. A clear diagram with the moments/effective pivot marked on should make it clear?
Edit - In essence, its a horizontal seesaw where the pivot (which has a upwards reaction - one hand) is 75 cm from one end and there is a weight at one end (downwards force - one hand) and the com represents the other weight (downwards force).
(edited 1 year ago)
Quick Reply
Related discussions
- Entry requirements
- A level options
- Mathematics Of Mechanics (yay)
- a levels needed for mechanical engineering?
- Choosing a maths degree
- Mathematics modules
- Stats and Mechanics
- Where can I find AS mechanics Edexcel questions ?
- Mechatronics engineering
- Advice to University Applicants ?
- Mechanical or aerospace engineering
- A-level Maths Study Group
- A-level Mathematics Study Group 2023-2024
- Worried about studying Chemistry at UNI
- A level physics or chem?
- just moved into uk curriculum from American..starting year 12 super confused
- Starting A-level content early
- Further Maths A-level *urgent
- What can I do to make up for no further maths?
- A level maths in engineering
Latest
Trending
Last reply 5 days ago
Did Cambridge maths students find maths and further maths a level very easy?Last reply 2 weeks ago
Edexcel A Level Mathematics Paper 2 unofficial mark scheme correct me if wrongMaths
71
Trending
Last reply 5 days ago
Did Cambridge maths students find maths and further maths a level very easy?Last reply 2 weeks ago
Edexcel A Level Mathematics Paper 2 unofficial mark scheme correct me if wrongMaths
71
